arc_fw_bufhdr
struct arc_fw_bufhdr *bufhdr;
wlen = sizeof(struct arc_fw_bufhdr) + wbuflen + 1; /* 1 for cksum */
rlen = sizeof(struct arc_fw_bufhdr) + rbuflen + 1; /* 1 for cksum */
bufhdr = (struct arc_fw_bufhdr *)wbuf;
memcpy(wbuf + sizeof(struct arc_fw_bufhdr), wptr, wbuflen);
bufhdr = (struct arc_fw_bufhdr *)rbuf;
memcpy(rptr, rbuf + sizeof(struct arc_fw_bufhdr), rbuflen);